Fuel Pressure - to augment or not to augment? Electronic fuel pump augmentation

[soundquest]

I am wondering how many of you have electronic fuel pumps in-line with the normal mechanical fuel pump and am wondering what benefits you have gained. Am also wondering how many of you are running stock mechanical fuel pumps without any issues to report? Thanks.

[Joe Johnston]

My cars sit weeks between using. I left the mechanical pump in place and use the electric to fill the carb. Starts right up with very little cranking. Once running I turn the electric off.

[tnswt12]

I run a mechanical and electric fuel pump on my '57 E-Code, and use it in the same manner as Joe Johnston described; otherwise, I likely would have gone through 3 or 4 starter motors by now. There is more going on here and one should not lay blame on starting issues entirely at the foot of the mechanical fuel pump.

If the mechanical pump has some hours on it, yes, it is possible it will lose some of its prime sitting weeks on end. However, the proper method to start the engine is to press the accelerator to the floor once, and release it, this sets up the choke, and if, the fuel bowls are loaded the engine should fire promptly. With hard starting, constantly pumping the accelerator pedal due to the absence of fuel in the carburetor does nothing but wear out the carburetor linkage, and internal parts of the carburetor—the carburetor is not a pump, that is a job left to the fuel pump.

In lieu of using an electric fuel pump the Thunderbird part houses now market a check valve for the fuel line. Some enthusiasts have found success with this fix, especially for shorter periods of nonuse. Casco part number 9160CV. I have not used this part.

With hard starting the biggest boogie-man issue we as hobby car enthusiasts face is the fuel we have available. Try this experiment and see for yourself just how quickly evaporation occurs. Using a marked glass, pour gasoline in the glass and leave it overnight. You will be amazed at the loss. And this experiment does not factor in the heat from the engine that is heating the fuel bowl in the carburetor after you switch off the car. Now, consider the time element and you can see that by the time you return to start your engine after weeks of inactivity, the fuel bowl is bone dry.

I find that with the use of the electric fuel pump that I installed in 2019, I save my starter motor, and I have quick starts. Switching the electric pump on for about 40-45 seconds after 2 weeks of inactivity, pressing the accelerator pedal to the floor once, and turning the cranking motor for no more than 5 to 8 seconds, usually starts the engine. If it does not start, I do not touch the accelerator pedal, instead I continue to let the electric pump work an additional 10 or 15 seconds, turn the key a second time, and the engine cranks. At that point, I switch the electric pump off. Understand there is a huge amount of current being transferred from the battery to the starter motor during cranking, so cranking should be performed in short, quick bursts, rather than, in a long continuous stretch.

The toggle switch that controls the electric pump is mounted within reach to the right of the steering wheel, under the dash. It cannot be seen unless you get down and look under the dash. Installing an Airtex E8016S electric fuel pump is quite a simple job. It mounts easily mid-way under the driver door on the outside of the frame. No drilling is necessary as there is a predrilled hole at this location where the frame brace is found. Painted black prior to installation renders the pump almost incognito. Wiring can be fished up through the shifter opening after being inserted inside a heat resistant mesh and routed to the dash area.

A hard starting issue is not an issue associated only with Thunderbirds. Complaints of hard starting can be found on any of the other vintage car hobby blog sites.

This is a long-winded comment, but I hope that this write-up helps you, or someone else down the road.

[soundquest]

Excellent write-up and very useful (both replies). This more than answers my question. Thank you.

[Jim G]

How do you add this electric pump- in-line cut to fuel line or tee fitting by-pass pump when not using electric? Check valve ? Or engine pump sucks fuel through electric pump in line when not switched on? Jim G